5 files changed, 106 insertions, 0 deletions

diff --git a/src/base/stats/info.hh b/src/base/stats/info.hh
index fa7c8cc3d..2c5b44a38 100644
--- a/src/base/stats/info.hh
+++ b/src/base/stats/info.hh
@@ -234,6 +234,20 @@ class FormulaInfo : public VectorInfo
     virtual std::string str() const = 0;
 };
 
+/** Data structure of sparse histogram */
+struct SparseHistData
+{
+    MCounter cmap;
+    Counter samples;
+};
+
+
+class SparseHistInfo : public Info
+{
+  public:
+    /** Local storage for the entry values, used for printing. */
+    SparseHistData data;
+};
 
 } // namespace Stats
 
diff --git a/src/base/stats/output.hh b/src/base/stats/output.hh
index 26c4c5bbd..9cd33a5f9 100644
--- a/src/base/stats/output.hh
+++ b/src/base/stats/output.hh
@@ -43,6 +43,7 @@ class DistInfo;
 class VectorDistInfo;
 class Vector2dInfo;
 class FormulaInfo;
+class SparseHistInfo; // Sparse histogram
 
 struct Output
 {
@@ -57,6 +58,7 @@ struct Output
     virtual void visit(const VectorDistInfo &info) = 0;
     virtual void visit(const Vector2dInfo &info) = 0;
     virtual void visit(const FormulaInfo &info) = 0;
+    virtual void visit(const SparseHistInfo &info) = 0; // Sparse histogram
 };
 
 } // namespace Stats
diff --git a/src/base/stats/text.cc b/src/base/stats/text.cc
index 45d59ff29..f8471f1a1 100644
--- a/src/base/stats/text.cc
+++ b/src/base/stats/text.cc
@@ -581,6 +581,92 @@ Text::visit(const FormulaInfo &info)
     visit((const VectorInfo &)info);
 }
 
+/*
+  This struct implements the output methods for the sparse
+  histogram stat
+*/
+struct SparseHistPrint
+{
+    string name;
+    string separatorString;
+    string desc;
+    Flags flags;
+    bool descriptions;
+    int precision;
+
+    const SparseHistData &data;
+
+    SparseHistPrint(const Text *text, const SparseHistInfo &info);
+    void init(const Text *text, const Info &info);
+    void operator()(ostream &stream) const;
+};
+
+/* Call initialization function */
+SparseHistPrint::SparseHistPrint(const Text *text, const SparseHistInfo &info)
+    : data(info.data)
+{
+    init(text, info);
+}
+
+/* Initialization function */
+void
+SparseHistPrint::init(const Text *text, const Info &info)
+{
+    name = info.name;
+    separatorString = info.separatorString;
+    desc = info.desc;
+    flags = info.flags;
+    precision = info.precision;
+    descriptions = text->descriptions;
+}
+
+/* Grab data from map and write to output stream */
+void
+SparseHistPrint::operator()(ostream &stream) const
+{
+    string base = name + separatorString;
+
+    ScalarPrint print;
+    print.precision = precision;
+    print.flags = flags;
+    print.descriptions = descriptions;
+    print.desc = desc;
+    print.pdf = NAN;
+    print.cdf = NAN;
+
+    print.name = base + "samples";
+    print.value = data.samples;
+    print(stream);
+
+    MCounter::const_iterator it;
+    for (it = data.cmap.begin(); it != data.cmap.end(); it++) {
+        stringstream namestr;
+        namestr << base;
+
+        namestr <<(*it).first;
+        print.name = namestr.str();
+        print.value = (*it).second;
+        print(stream);
+    }
+
+    print.pdf = NAN;
+    print.cdf = NAN;
+
+    print.name = base + "total";
+    print.value = total;
+    print(stream);
+}
+
+void
+Text::visit(const SparseHistInfo &info)
+{
+    if (noOutput(info))
+        return;
+
+    SparseHistPrint print(this, info);
+    print(*stream);
+}
+
 Output *
 initText(const string &filename, bool desc)
 {
diff --git a/src/base/stats/text.hh b/src/base/stats/text.hh
index 24abaac97..7f7edaa91 100644
--- a/src/base/stats/text.hh
+++ b/src/base/stats/text.hh
@@ -67,6 +67,7 @@ class Text : public Output
     virtual void visit(const VectorDistInfo &info);
     virtual void visit(const Vector2dInfo &info);
     virtual void visit(const FormulaInfo &info);
+    virtual void visit(const SparseHistInfo &info);
 
     // Implement Output
     virtual bool valid() const;
diff --git a/src/base/stats/types.hh b/src/base/stats/types.hh
index 9faa8d33d..831cc6db5 100644
--- a/src/base/stats/types.hh
+++ b/src/base/stats/types.hh
@@ -32,6 +32,7 @@
 #define __BASE_STATS_TYPES_HH__
 
 #include <limits>
+#include <map>
 #include <vector>
 
 #include "base/types.hh"
@@ -42,6 +43,8 @@ namespace Stats {
 typedef double Counter;
 /** vector of counters. */
 typedef std::vector<Counter> VCounter;
+/** map of counters */
+typedef std::map<Counter, int> MCounter;
 
 typedef std::numeric_limits<Counter> CounterLimits;